Metallic bellows



April 29, 1980.

METALLI C BELLOWS Filed Deo. 3, 1925 c. L. LEE 1,756,911

Plazma Apr. 29, 1930,

UNITED srA'rss PTENT oFFlcE L. Luz, o! nnnorr, moment, assmnon 'ro Gaiman. mo'rons oonromnon, or mnorr, moment, A ooarona'rron or Dnnawm IETLLIO BELLOWS Application led December 8, 1985. Serial Ro. 78,087.

|This invention relates to the form and structure of a metallic bellows adapted to withstand the strain of rapid expansion and contraction for very long periods without danger of rupture. i o

It consistsin the particular. form of the walls of a tubnlar metallio bellows, and more particularly inthe contour of the oiroumferential ridges and alternatin grooves that form the corrugations, which is such that the bnding st applied in the expansion and contraotion of the bellows will be distributed mainl like reference c aracters indioate like parts p its normal form "ao throughout its several views:

Fi 1 is a side view, partl'y in section, of a meta lic bellows made of a plurality of assembled annular sheet metal elements;

Figs. 2 and 3 are Sections of the two kinds of elements, of which the bellows illustrated is mainly oomposed, as they appear before bein assembled'. a

the embodiment illustrated,which is that now preferred, indicates a bellows tube in (the form it assumes when not aeted on by unbalanced forces) without end attachments, oonstructed of. a -plurality of pairs of' annular plate like elements composed of sheet metal punched from flat sheets and pressed into the forms shown in Figs. 2 and 3. The element or plate indicated b numeral 21 in Fi 3 has an outer perip eral flange 22 of cy 'ndrical form merging 'into an annular flat surface 23 normal to the axis of the c lindrical flange 22 and the entire element. mmediately inside of this flat portion 23, the plate is curved or dished at 24 in an annular zone, curved in. any radial plane in an are of somewhat over 90 degreee. Said plate is pressed into conoidal form as at 25, the intersection of any radial plane with the surface of said conoidal portion being a line tantial to the radial eurvature of the zone 24.

eonoidal part 25 extends inward to a circular line near the inner periph'ery of the element where'-radial lines on said conoidal portion become substantially tangent to another annular zone or dished portion 26 curved in radial planes to an angular extent somewhat more than 90 degrees and in a direction reverse of the curvature of the zone 24.

The dished zone 26 terminates in a flat flangelike portion 27 which is in a plane parallel to, but offset with respect to the ortion 23.

Element or plate 30 illustrated 1n Fig. 2 is similarly formedwith inner and outer annular zones radiallycurved, but element 30 has a cylindrical flange 31 at itsinnerperiphery instead of at its outer periphery as at 22 in plate 21. The relation of the flanges and curved zones is such that the plates may be assembled-with curves reversed with respect to each other as shown in the drawings. The flat portion or flange 32 of element 30 corresponds to the Vflan e 27 of plate 21 and rests in contact with it w en the two elements are assembled; the annular zone or dished portion 33 corresponds to the portion 26 of plate or element 21; the conoidal part 34 and the dished annular zone 35 to the dished zone 24 of element or plate 21. The peripheral plane flange 36 corresponds to the flat part 23 of element 21 and fits in contact with 'the part 23 of a matched plate 21.

The bellows is made by staokin plates 21 and 30 alternately, the flange 22 tting over the outer edge of plane flange 36 of plate 30, and the flange 31 of late 30 extendin through the central opening in plate 21 sai flange fitting about the flat flange 27 of said plate. When suflicient plates have been stacked, to bring the bellows to the required length, each cyhndrical flange 22 and 31 of plates 21 and 30, respectively, are spun over the adj acent flat flan es 36 and 27 The several joints may then e soldered.

It is of course, obvious that each joint can be made and soldered se arately, but the preferred method is to app y solder paste to the flan es, or tin them during or before the stac ing; then to spin the cylindrical flanges over the mating flatones and, by heating the whole assembly, solder all of the joints in one operation.

It should be noted that the bellows'of the form shown has its convolutions so separated that the radial-section curve formed by dished portions 26 and 33, and forming the bottom of the curve of a corrugation, has a longer radius than the radial-section curve adjacent the edge of the ridges formed by dished portions Qt and 35. The dished portions 24-35 and 26-33 individually forming an arcsomewhat over 90 of a circle, as has been nientioned before, will, When assembled, form in radial section curves of slightly more than 180 degrees. T hus, in the normal or untensioned condition of the bellows, the external grooves are Wider at their` bottoms than at their tops, or wider at their closed edges than at their open ones,-that 'is, measured longitudinally of the axis of the bellows,-While the internal grooves (within the ridges) are reversely proportioned. The ratio of the radius of the semi-circular crosssection formed by dished portions 24 and to the radius of the semi-circular cross-section formed by dished portions 26 and 33, is substantially equal to the ratio of the diam- V eter of the central opening in the plates to the diameter of the outer edgeof the plates.

By constructing the bellows in this proportion, the bending stresses occasioned by extension and compression of the bellows arev distributed more largely upon the conoidal portions 25 and 34 of the various plates than .in similar known structures and, consequently, a longer life of the bellows obtains. In other words, the radial curvatures of zones 24 an'd 35, and 26 and 38 arefproportioned substantially to compensate 'for-the difi'erences in the amounts of metal in the two Chief bending regions of the plates owing to their' difference in circumferential extent. Thus, continual contraction and expansion of the bellows will tend to flex the conoidal portions 25 and 34 to a substantiall greater degree than the dished portions, t e flexing of the plates being gradually diminished in the direction of the juncture between adjacent plates.

In Fig. 1, the two extreme plates may be so eonstructed that the bellows may be attached to any desirable device. The element to the left- (as viewed in Fig. 1) has an outer cylindrical flange, which may be spun overthe edge of any device to which this end of the bellows is to be secured, while the op osite extreme plate is provided with a w1 e flat flange which may be secured to any device by means of clamping, screwing, or any other suitable manner. c

The present form-.of metallic bellows is peuliarly' adapted to be used'in devices including a bellows which is subjectd to rapid l T changes in Shape orlength. It has been successfully used m connection with fuel pum s of the ty e disclosed in the copending app ication ofp Charles F. Kettering and Charles L. Lee, Patent No. 1,607,200, November 16, 1926, in which the .bellows displacement member is operated at comparatively high speed.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scopeof the claims which follow.

`What is claimed is as follows 1-,

1. A metallic bellows in the form of a tube with circumferential 'corrugations, the 'tops of the ridges and thebottomsof theA grooves of the vcorrugations being curved'upon'arcs of circles of different radii, and the ratio of the radius of the bottom of the groove to the radius of the top of the ridge being in the neigh- ,borhood of lthe ratio'of the diameter of the outer circle of the tube forming theitopsi of said ridges to the 'diameter of the inner cir-' cle of the tube forming thebottoms ofthe grooves. c

with circumferential corrugations, the tops of the ridges and the bottoms of thegrooves of -the corrugations bein curved upon arcs of circles of different ra ii, andl having. the 4 curved bottoms andtopsof the grooves connected by intermediate conoidal portions, the difference between said radii bein such as to compensate for the difference in t e amounts of metalin the .curvedportions 3. A metallic bellows comprising a tubular body having circumferentlal' corrugations forming external grooves separatedby ridges that inclose internal grooves; vthe bottoms of said internal' and externalgrooves being curvedin longitudinal radial anesforming -substantially equal Curved areas. 1

'tudinally of the axis of the bellows, than their open edges.

6. A bellows as lows being composed of reversely matched sheet metal elements united 'by interlocled seems.

' In testimony whereof I aflix my si ature.A

' CHARLES L.. EE.

2. A metallio bellows in theform of tube i defied in ciai'ni'a, said beiaaa 

